As data centers embrace virtualization technologies, more and more data center networks are adopting overlay technologies over a CLOS network based architecture, in which Operation and Management (OAM) functions are very important for daily management and performance monitoring. Examples of overlay technologies include Cisco System's Virtual Extensible Local Area Network (VxLAN) and Network Virtualization Overlays (NVO3).
Software-defined networking (SDN) centralizes and simplifies control of network management by allowing network administrators to manage network services through abstraction of higher-level functionality. Such an abstraction and simplification is well aligned with the evolution of the data center network.